Gusset bags or pinch bottom bags with easy opening features are well known. Certain such bags are provided with selectively disposed arrays of abhesive. An example of such a bag is shown in U.S. Pat. No. 3,708,106. Other bags are provided with tear strips to facilitate opening, such as the bag shown in U.S. Pat. No. 2,415,139. Still other bags are provided with recloseable tin-ties, such as the bag shown in U.S. Pat. No. 3,719,318. Bags also have been made with separate plastic or metal clip members such as the bag shown in U.S. Pat. No. 4,142,346.
Securely closed bags provided with tear strips such as strings, or hot melt sticks are desirable in many instances where a strong closure is required and where it is necessary to protect against sifting or leaking of the material stored in the bag. Bags of this type are closed by folding the extreme ends of the gusset panels in to face-to-face relationship with one another. A tear strip of some sort then is affixed on either the front or back wall of the bag. The extreme top end of the bag then is folded over the tear strip and is secured in this folded condition. The bag can be opened by pulling on the tear strip, thereby at least partly severing the folded top portion of the bag.
Although many bags of the above described general construction have proved quite functional, it has become desirable to provide a securely closed but easy opening bag with a tear strip that can readily accomodate material of substantial weight. In the prior art bags of this type, it has been found that when the bag is manufactured from a heavy gauge of material, it has been difficult to accurately and reliably advance the tear strip through the material. A continuous array of perforations extending across the bag facilitates the initial opening of the bag, but can make the bag undesireably weak. In the past, high strength bags of this type have addressed this problem by providing fewer plies of material in the top folded over portion of the bag. However this also can make the bag too weak. Still others have addressed this problem by incorporating abhesive adjacent the top closure. Although certain bags, with abhesives are functional, and can be opened easily, abhesives generally have not facilitated the use of tear strips.
In view of the above, it is an object of the subject invention to provide a pinch bottom or gusset bag that can be easily opened by a tear strip.
It is another object of the subject invention to provide a pinch bottom or gusset bag that can securely retain a substantial weight of material but can be easily opened.
It is an additional object of the subject invention to provide a pinch bottom or gusset bag that does not require the use of abhesives.
It is a further object at the subject invention to provide a pinch bottom or gusset bag having a tear strip opening wherein the tear strip reliably will provide a clean severence of the top portion of the bag.